Circuit-breaking mechanism for internal-combustion engines



I. El TUSCHEB.

CIRCUIT BREAKING MECHANISM FOR INTERNAL COMBUSTION ENGINES APPLICATION mi!) MAY 20, 1920.

1,350,898. Patente Aug. 24, 1921").

2 SHEETS--SHEET I.

J. E. TUSCHER.

CIRCUiT BREAKING MECHANISM FOR INTERNAL COMBUSTION ENGINES. APPLlcATloN HLED MAY 2o, 1920.

1 ,350,898, Patented Aug. 24, 1920.

2 SHEETS-SHEET 2.

as -29 A NNNNNN JEAN EDOUARD TUSCHER, OF NEUCHTEL, SWITZERLAND.

CIRCUIT-BREAKING MECHANISM FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Aug. 24, 1920.

y -I yApplication filed Hay 20, 1920. Serial No. 383,010.

time of ignition to be varied automatically4 according to the speed of the engine.v It can be fitted to ignition magnetos and renders it possible to transform them immediately into magnetos giving an automatic advance of ignition without increasing the over-all dimensions of the magneto.

The mechanism is based on the principle of the centrifugal governor. It comprises a device which rotates with the armature of the magneto and carries contacts inserted in the circuit to be broken, one of which is movable and is moved away from the other at desired intervals by one or more fixed abutments so as to break the circuit. This arrangement, of which the principle is known, is characterized by the fact that the rotary member can move relative to the armature which drives it through the intermediary of a governor-mass which pivots upon this member, bears against the armature and is subjected to centrifugal force. The pivotal movement of this mass under the action of centrifugal force produces the displacement desired, said displacement being variable as a function of the centrifugal force, and consequently, of the velocity of rotation, thereby causing a corresponding variation in the time or times of ignition. The present invention also relates to a particular form of the said movable contact or catch-lever, which is constituted by a curved lever pivoted near its center on the rotary member, and carrying at one extremity a contact and, at the other, a striker which comes into contact with the stationary abutment or abutments. This lever is characterized by the fact that it is brought back to circuit-closing position by a A coil-spring under compression which bears against the portion carrying the contact and against the rotary member, and also by the fact that the portion which carries the striker is of greater mass than .6.1.1.9 9th?? Portion, S0 thai under the action of centrifugal force, the lever has a tendency to hold the contacts against each other, its action being added to that of the spring, so as to obtain a more abrupt break each time the lever is actuated by the fixed abutment or abutments. The said lever is also arranged in a special manner as regards its operation under the forces which act upon it, its insulation and the manner in which current is fed to it.

According to a modification, the spring which brings back the lever to its circuitclosing position is a leaf-spring fitted within the curve of the lever, and also serves to feed the current to the lever owing to the fact that its extremity, which bears against the movable rotary portion, is connected to the central portion, fixed to the armature but insulated therefrom, by a coiled spring which allows the current to pass. This coiled spring also serves to bring back the displaceable rotary portion to its original position relative to the said central portion and the force of this spring is calculated in accordance with the range of adjustment to be given to the apparatus.

The invention is illustrated diagrammatically, for explanatory purposes only, and in no way limitatively, in the accompanying drawings in which:

Figure 1 is a front view of the mechanism, and

Fig. 2 is a section along the broken line 2-2, Fig. 1.

Fig. 3 is a view, similar to Fig. 1, of a. modification.

Fig. 4 is a section along the broken line 4 4 of Fig. 3.

The mechanism according to the invention comprises a rotary member or disk 1 which rotates with the armature ofthe magneto. With this end in view, it is mounted on a. central portion in two pieces 2 and 3, one ofv which is screwed into the other and secured by a pin 4. The disk 1 can rotate on the reduced portion 5 of the part 3 between a flange 6 of the part 2 and a shoulder 7 on the part 3, but it must here be stated that this movement of rotation is limited and takes place under predetermined yconditions, as will be explained below.

The part 2 has the form of a truncated cone and is keyed to the cheek of the armature, ground-connected lin the usual manner Ito the armature which forms one of the .poles of the primary circu/f and this part 2 is held in place by means of an insulated screw 8 passing through a sleeve 9 ot insulating material, ent 'ainment being insured by a key 10. vThe screw 8 is screwed into the insulated pole otthe condenser ot the magneto (not shown) which constitutes the Yother pole oi the primary circuit et the magneto. This method ot keying thepart 2 is similar to the usual method oit keying circuit-breakers used with known magnetos.

The part 3 is cylindrical in trent and is intersected by a notch, the prolile 11 of which is `designed according to a delinite law, as will Vbe seen below, and it acts as a cam. Y

@n a shaft 12 fixed to the rotary member' or disk 1 there is pivoted a governing mass 13, which is under the influence of centrifugal torce, and a prolongation, or iinger, 141 ol this mass bearsagainst the cam 11 ot the central part 3. A spring 15 .mountedv in a torus-shaped recess 1G in the part 3 bears, on the one hand, against this part and, on the other hand, against a tace 17 perpendicularto the planeet the disk 1; in `this manner `it tends continuously to rotate the disk 1 in the opposite direction to that indicated by the arrow 18andthereby to bring I the Imass 13 back `to the position shown in `13 is llimited by the fact that the shoulder e, 7J strikes against the central boss 19 along al, 1.

The catch-lever of the circuit-breaker consists of a twofaigmed leverf20, 21; this lever can pivot about an axis 22 ot the disk 1 and an insulating lsleeve 23 is interposed between the lever and the axis V22. The lever is held on the Aaxis 22 `by a screw 24e and by LIrlfans ort an insulating washer 25, IaV

leaf 26 which feeds current thereto from the insulated .screw 8 upon which it bears, and a compressedcoil spring 27 .mounted in ya .circular recess in thelever, concentric with the insulating sleeve 23. This arrangement permits oit Aclamping the screw 24 on the airis 22 while, at the same time permitf ting ol relativemovement between the lever and the leaf 26 and insuring perfect electric contact.

The arm 21 of the lever `carries an in sulatedstriker 28 designed to `come into contact, `during rotation, with .the `iixed abutmsllt er abilmente (not Shown) carried by a circular casing, these abutments being arranged along a circle indicated in part in dot and dash lines inFig. 1.

rlhe arm 2O carries a platinum-.covered contact 29 which hears against a platinumcovered contact 30 constituted by an ad" instable screw which screws into a boss 31 on the disk 1 and has a lock-nut 32. The

.screw 30 is grounded b a carbon-contact 33 mounted inthe rear 'face of the disk 1, behind the boss 31 and continuously pressed b a syrinO Se against the cheek of the f lhis` arrangement et the returning-spring is very advantageous and terms one ot the characteristics ot the invention.

Another characteristic ot the invention ref sides inthe-tact that the arm 21 ot the lever is of greater mass than the arm 20, so that during rotation this arm 21, moving away under the action ot centrifugal force, and aiding the action ot the spring 35, tends to press the ytwo contacts 29,80 firmly against each other, so that a bettereleetrical engagement is had.

@n the other hand, in view ot the `resistance of the lever to movement, which resistance is due to the spring and to centrifugal torce acting on the arm 21, it is advisable to make it longer than is `customary, so :that vwhen the fixed abutments come in contact with the striker, the shock is not too great, while being sufficient to cause breakage ot ,the circuit. Otherwise, the shock would act in antagonism to the action et' the centrifugal mass and would hinderits action. 1t .is tor these reasons that the inventor has constructed the lever Vinthe manner described, in which, in view .of the length of the arm 21, the resultant oit the shock and the other Yforces acting on the lever passes through theaxis of rotation ot the whole mechanism. Y

rlhe whole oi" the mechanism is balanced about the axis of rotation both .trom a static and from a dynamic point ot view, subject to the reserves made for the movable portions subjected to centrifugal iorce.

vrEhe mechanism operates `as follows:

Suppose .the whole `to be rotating in the direction of the arrow 18 Fig. 1, at a speed less than a given speed, the centrifugal force acting on the mass 13 is not su'llicient to overcome the pressure of the sprii'ig 15, and the 13 remains in the position shown in by the cam 11 of the central portion 3, 2 rotating with the armature in the direction of' the arrow 18, which cam acts upon the finger i4 which it tends to push outwardly. Breakage oli' the primary circuit (constituted by the parts 8, 2G, 27, 20, 29, 3i), 31, 33, between one c i the poles of' the comlenser of the magneto and the cheek of the armature connerted to ground) takes effect between the ontacts 25), 3i), each time the circuit-breaker 2i), 21 swings, that is to say, each time the striker meets the fixed abutment or abutinents on the casing. The point or points ot ignition. do not vary so long as the given value of the speed is not attained.

As soon as this value is attained and in proportion as the speed increases after having exceeded it, the mass 13 moves outwardly against the action of the spring 15 and the finger 14 abuts against the cam 11 and displares the entire mechanism relative to the central portion 2, 3, in the direction of the arrow 18, that is to say, it effects an advance in the ignition, the speed still rises this displacement is accentuated and the advance in the ignition 'is increased. If the speed decreases the displacement takes place in the opposite direction. It can therefore be said that the variation in the point or points of .ignition Vcorresponds automatically to the variation in speed.

The automatic variation in the ignition can be made proportional to the variation in speed or a function of this speed, according to a law `which can be chosen at will. For this purpose it is sufficient to determine the form of the finger 14 or of the cam 11, or of both of these parts by means of suitable diagrams.

It will be obvious that more than one gov orner-mass may be provided, and that the casing, not shown, which carries the fixed abutments may be displaced at will so as to vary the point of contact between these abutments and the striker; however, once the casing is brought to a certain position it can be considered as fixed, as well as the abutments which it carries, which then have no influence on the automatic variation of the points of ignition.

The central portion Q, 3, instead of being connected to the cheek of the armature might be constituted by an integral part of this latter.

ln the modification shown in Figs. 3 and 4, the spring 38 which brings back the lever 20, 21 to its circuit-closing position is a leafspring fitted in the curve of the lever. This spring 38 bears on the arm 21 to which it is fixed by a screw 381 passing through a slot in the end of the spring 38. The other end ot' this spring bears on an insulated piece 39 fixed on the disk 1. In order to feed the current from the central screw 8 to the lever 20. 21 a rod 40 is screwed into the sleeve 41 insulated by a sleeve 42 from the central portion 3. This rod is also insulated from the central portion 3 and it also serve's to hold the parts 3, 41 and 42 together. A helical-spring 43 is attached, on the one hand, to the free end of the rod 4() and., on the other hand, to the end ot the spring 38 which bears against the insulated member 3S). In this way, current is f'ed from the central screw 8 to the lever 20, 2l by the rod 40, helical spring 43, leaf spring 38 and screw 381.

The helical spring 43 plays, in this case, the part of the spring 15 and serves to restore the displaceable rotary member or disk 1 to its original position relative to the central portion 3 and the strength of this spring is calculated according to the degree of adjustment to be given to the apparatus. Furthermore, a slight secondary adjustment can be obtained by varying the position of the spring 38 relative to the arm 21 of the lever by sliding the screw 381 in the slot in the spring 38.

The method of operation of the' apparatus according to Figs. 3 and 4 is the same as that shown in Figs. 1 and 2.

I claim:

1. A circuit breaking mechanism for internal combustion engines comprising a disk, a contact carried by said disk, a two-armed lever fulcrumed on said disk, a contact carried by one arm of said lever for engaging the first mentioned contact, yieldable means carried by said disk and bearing against said arm of the lever for holding the contacts normally engaged, a striker carried by the other arm of said lever adapted to move the contacts apart, a hub for said disk having acam portion lying in the same plane with said lever, a weighted arm pivoted on said disk in the same plane with said lever and having a nose adapted to cooperate with the cam portion of said hub whereby to shift the disk when the weighted arm swings outwardly under the influence of centrifugal force, and means to yieldably holdv the hub and disk in an initial position against the action of said nose on said cam, substantially as described. A

2. A. circuit breaking mechanism for internal combustion engines comprising in combination a disk rotating with the armature of the magneto but shifta-ble with respect thereto, a hub about which said disk is fitted to rotate having a cam portion, means arranged between the hub and disk for yieldably holding the disk in an initial position with respect to the hub, a weighted arm pivoted on the disk and having a nose adapted to cooperate with the cam portion of the hub for moving the disk relatively thereto when the arm swings outwardly under the influence of centrifugal force, a twoarmed lever pivoted on the other side of the disk from said weighted arm, a striker carried by one arm of said lever for oscillating the same, contacts supported by said disk and. the other arm of said lever, and means to normally hold the contacts closed, substantially as described.

3. A circuit breakii'ig mechanism for internal combustion engines comprising in combination a disk rotating with the armature oi the magneto but shiitable with respect thereto, means adapted upon the rapid rotation of the disk to shift said disk with respect to the armature of the magneto, a

tivo-armed contact lever pivoted on said disk, fixed abntments adapted to engage said Contact lever to break the circuit, yieldable means to hold the contact lever in the circuit closing position, and a spring biasing the disk to initial position, said spring being located in a torus-shaped recess, substantially as described.

Il. fi circuit breaking mechanism for internal combustion engines comprising in combination a disk, a hub on Which the disk is free to rotate, said hub having a torusshaped recess therein, an arm carried by the disk, a spring iitted between said arm and the torus-shaped recess for yieldably coupling the disk and hub together, means on vs )ect thereto a centrifugal Governor-mass 7 b 13 pivoted on said disk, a cam-face rotating with the armature, a finger on said governor mass adapted to coperate with said camace, a two armed Contact lever pivoted on said disk, iixed abntments adapted to engage said contact lever to break the circuit, said linger acting through said cam-face to vary the position of the disk relative to said armature spring acting to hold the contact-lever in the circuit closing position, a spring acting against the centrifugal governor mass, said spring being located in a toruseshaped recess in said disk and a leaf-spring for leeding current from the armature to said contactlever. i

JEAN EDOUARD TUSGHER. 

